No time is a good time to abuse pastures by overgrazing, shortening rest periods, or overstocking, but fall is an especially bad time for such agrarian offenses.
“Management decisions made during the fall affect the ability of the plants to overwinter, determine when new growth is initiated in the spring, and impacts how much total forage growth will be produced over the following season,” says Gene Pirelli, professor emeritus in animal and rangeland sciences with Oregon State University.
When pastures are overgrazed or subjected to excessive forage harvesting in the fall, it inhibits root system rebuilding and the formation of shoots for spring growth. Pirelli explains that roots regenerate in the fall while potential new shoots are also in the process of forming. Plants need time to store carbohydrates to ensure long-term forage production.
“The lower stems or crown, rather than the roots, are the major storage unit of complex carbohydrates in perennial grasses,” Pirelli states. “The new root system will take up water from the soil plus important nutrients that nurture those new growing points. Both plant systems must work together to sustain pasture growth in the next grazing season.”
The actual time it takes for new root growth varies depending upon the amount of moisture from irrigation or rainfall, daylength, and the residual stubble height. New plant roots are evident if plants are dug up and washed free of any soil. The new roots will be white, variable in length, and originate from the crown.
Plant growing points develop in the fall, which provide next spring’s forage growth. Pirelli contrasts these young grass shoots, or tillers, to human babies — both need a steady supply of nutrients and protection from stress. In the fall, nutrients are supplied from the previous season’s tillers, which have stored carbohydrates in the bottom 3 to 4 inches of the plant. The existing tillers are often dormant and brown during fall — but not dead — and their storage function is critical. The older tillers also provide physical protection to the new tillers.
If pastures are grazed or mowed lower than a 3- to 4-inch stubble height in the fall, the plant’s carbohydrate reserves are reduced, and the new tillers are robbed of their food source. Also, the new tillers are exposed to weather extremes. Overgrazing also slows or stops root formation, and in the following spring, the new tillers grow slower and have fewer roots for needed nutrients.
Grass species vary in how sensitive they are to grazing or cutting height. The following recommendations provide a minimum residual height for some common grass species: orchardgrass and tall fescue: 3 to 4 inches; KY Bluegrass: 2 to 3 inches; perennial ryegrass: 2 inches; tdwimothy: 4 to 6 inches.
Join us at the Trimble County Extension Service on Tuesday, November 8, 2022 at 6 p.m. for a program on Hay Testing and Winter Rationing. Call 502-255-7188 for more information.
Source: Mike Rankin, Hay and Forage Grower. Go to hayandforage.com for more articles.
(0) comments
Welcome to the discussion.
Log In
Keep it Clean. Please avoid obscene, vulgar, lewd, racist or sexually-oriented language.
PLEASE TURN OFF YOUR CAPS LOCK.
Don't Threaten. Threats of harming another person will not be tolerated.
Be Truthful. Don't knowingly lie about anyone or anything.
Be Nice. No racism, sexism or any sort of -ism that is degrading to another person.
Be Proactive. Use the 'Report' link on each comment to let us know of abusive posts.
Share with Us. We'd love to hear eyewitness accounts, the history behind an article.